In the proposed studies, the investigators plan to use mineralocorticoid receptors to study the relative contributions to the plasma mineralocorticoid activity and to evaluate whether steroids other than aldosterone, deoxycorticosterone and cortisol contribute significantly to the plasma mineralocorticoid activity in low-renin hypertension. Several patients have been identified that appear to have such a steroid(s); attempts are being made to isolate this with the use of the receptor in a radioligand assay.